Device for transmitting information between a fixed location and a railway vehicle

ABSTRACT

THIS DISCLOSURE RELATES TO A PERIODICALLY CROSSED CABLE LOOP WHICH IS POSITIONED BETWEEN TWO RAILS OF A RAILWAY FOR PERMITTING THE EXCHANGE OF INFORMATION BETWEEN A CENTRAL LOCATION AND A RAILWAY VEHICLE. THE DISCLOSURE IS CHARACTERIZED BY THE FACT THAT ONLY ONE SIDE OF THE PERIODICALLY CROSSED CABLE LOOP PLACED IN THE AXIS OF THE RAILWAY IS COUPLED TO AN ANTENNA POSITIONED ON THE RAILWAY VEHICLE IN ORDER TO REDUCE INTERFERENCE. THE ANTENNA IS HORIZONTAL AND DISPOSED PERPENDICULARLY TO SAID ONE SIDE OF THE PERIODICALLY CROSSED CABLE LOOP AND SYMMETRICALLY WITH RESPECT THERETO.

United States Patent Inventor Christian Jauquet Charleroi, Belgium Appl. No. 800,580

Filed Feb. 19, 1969 Patented June 28, 1971 Assignee Ateliers De Constructions Electriques De Charleroi (ACEC) Societe Anonyme Charleroi, Belgium Priority Feb. 21, 1968 Belgium P1154831 DEVICE FOR TRANSMITTING INFORMATION BETWEEN A FIXED LOCATION AND A RAILWAY VEIIICLE I Claim, 2 Drawing Figs.

Primary Examiner Kathleen H. Clafly Assistant Examiner-Williarn A. Helvestine AttorneyRaymond A Robic ABSTRACT: This disclosure relates to a periodically crossed cable loop which is positioned between two rails of a railway for permitting the exchange of infomnation between a central location and a railway vehicle. The disclosure is characterized by the fact that only one side of the periodically crossed cable loop placed in the axis of the railway is coupled to an antenna positioned on the railway vehicle in order to reduce interference. The antenna is horizontal and disposed perpendicularly to said one side of the periodically crossed cable loop and US. Cl. 179/82 Int. Cl H0411 5/00 Field of Search 1. 179/82 symmetrically with respect thereto.

1O 1 1 a 10 i W i ts I DEVICE FOR TRANSMITTING INFORMATION BETWEEN A FIXED LOCATION AND A RAILWAY VEHICLE This invention relates to a device for transmitting information between a fixed location and a railway vehicle.

Various devices are known permitting the exchange of information between a central location and a railway vehicle and the transmission of instructions to the vehicle in the case of automatic or semiautomatic operation thereof. These devices use, as a linking element, a cable forming a periodically crossed loop positioned between the two rails of the railway and one or more antennas positioned on the locomotive and coupled to the loop. Such a loop is usually fed by signals originating from a central location and comprises two conductors generally fixed on the upper portion of the base of the rails. The conductors are crossed at regular intervals in such a way as to form marking points where the phase of the signals is inverted, and the counting of these points permits to measure, aboard the locomotive, the distance travelled by the vehicle. The drawback of such a loop is that if two vehicles are located simultaneously on the same railway section between two crossings of the conductors, their axles form with the rails a closed circuit in which the loop induces currents which circulate. As this circuit is strongly coupled with the loop, the induced currents interfere with the flux of the loop in such a way that the transmission of information does not work anymore. To overcome this drawback, it has been suggested to reduce the coupling of the interfering circuit with the loop by moving the two conductors of the loop towards the center of the railway. In such a way, the interference is reduced but not completely and the transmission is appreciably impaired because of the narrowness of the loop.

The present invention overcomes all the above drawbacksv It concerns a loop ensuring a very good transmission of information and which is not sensible to disturbing circuits of the type disclosed above. It is characterized by the fact that only one of the sides of the loop, placed on the axis of the railway, is coupled to the antenna or to the ferrite antennas used on the locomotive, the antennas being horizontal and disposed perpendicularly to said side of the periodically crossed cable loop and symmetrically with respect thereto.

The invention will now be disclosed with reference to the accompanying drawings illustrating, by way of example, a preferred embodiment of the invention.

In the Drawings:

FIG. 1 illustrates a known'loop; and

FIG. 2 illustrates a loop in accordance with the invention.

FIG. ll of the drawings illustrates a periodically crossed cable loop, fed by signals originating from a central location, not shown, positioned between two rails 1 and 2 of a railway and comprising two conductors 3 and 4 constituting a cable generally secured to the upper portion of the base of the rails. The conductors 3 and 4 are crossed at regular intervals at points 5 in such a way as to form marking points where the phase of the signals is inverted, and the counting of these points permits to measure, aboard the locomotive, the distance travelled by the locomotive. If two railway vehicles are located simultaneously on the same section of the railway between two crossings of the loop, their axles 6 and 7 form with the rails l and 2 a closed circuit in which the loop induces currents which circulate as indicated. by the arrows. Because the circuit is strongly coupled to the loop, the induced currents interfere with the flux of the loop in such a way that the transmission of information does not work anymore.

The following description and FIG. 2 of the drawings relate to a particular embodiment of the invention. FIG. 2 illustrates a periodically crossed transmission loop consisting of two conductors 8 and 9 disposed between two rails 11 and 2 of a railway. These conductors are alternately crossed at points 10 for measuring the distance travelled by the train as disclosed above. One of the sides of the loop is secured to the base of the rail l and consequently strongly coupled magnetically to the rail 1. The other side of the loop is placed in the center of the railway at equal distances from each of the two rails. The

closed circuit formed by the two rails I and 2 and the two axles 6 and 7, which happen to be located simultaneously on the same section of the railway between two successive crossings 10 of the loop, is induced by the conductor 9 which produces in the two rails l and 2 currents which are equal and in opposition, and consequently have no action in the axis of the railway because they are at equal distances from the conductor 9. By placing on the locomotive a ferrite antenna 11 disposed horizontally, perpendicularly to conductor 8 and symmetrically with respect thereof, it is easy to see that such antenna will be influenced by the central conductor alone and that the closed circuit formed by the presence of the two axles 6 and 7 will not have any disturbing effect thereon.

The periodically crossed transmission loop may obviously be designed with marking points other than crossings without departing from the scope of the present invention.

1 claim:

ll. Transmission device between a fixed location and a railway vehicle including a cable forming a loop disposed between two rails of a railway and at least one antenna positioned on said vehicle and coupled to the loop, said loop having crossings at predetermined distances, characterized by the fact that one side of this periodically crossed cable loop is placed in the axis of the railway and coupled to said antenna located on the vehicle while the other side is secured to the base of one of the two rails, said antenna being horizontal and disposed perpendicularly to the side of the periodically crossed cable loop which is placed in the axis of the railway and symmetrically with respect to said side. 

